This is a repository for all cool scientific discussion and fascination. Scientific facts, theories, and overall cool scientific stuff that you'd like to share with others. Stuff that makes you smile and wonder at the amazing shit going on around us, that most people don't notice.

The sun is not yellow at all. It actually shines pure white, as white as snow. Only on the earth, when light streams through Earth's atmosphere, does the sun look yellow..

Color of the Sun

In popular culture, the Sun is yellow. But did you know that the color of the Sun is actually white? It’s only when light from the Sun passes through the Earth’s atmosphere that in changes in color, from white, to the yellow we see here on Earth.

All stars have a color. From red dwarfs and red giants, to white and yellow stars to blue giants and supergiants. The color of a star comes from its temperature. As photons escape the interior of a star out into space, they have different amounts of energy. A star can be emitting infrared, red, blue and ultraviolet light all at the same time. They’re even emitting X-rays and gamma rays.

If a star is cool, less than 3,500 Kelvin, its color will be red. This is because there are more red photons being emitted than any other kind of visible light. If a star is very hot, above 10,000 Kelvin, its color will be blue. Once again, because there are more blue photons streaming from a star.

The planes wheels have nothing to do with its forward velocity. They are just rotating freely on the conveyer belt.

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That rabbit is crazy; I'm Brian Waters!

Kotter: "You are lucky I'm truly not the vindictive or psycho type...I'd be careful from now on, and I'd just back the hell off if I were you....otherwise, the Mizzou "extension office" life might get exciting"

Polar bears aren't actually white. They have colorless transparent fur. Their outer layer of fur is not white, but completely transparent, consisting of clear hollow tubes. Polar Bears are nearly undetectable by infrared cameras, due to their transparent fur.

Around a trillion neutrinos from the Sun will pass through your body while you read this sentence.

The Sun is one among the 200 billion stars in our Milky Way galaxy.

The Sun is one among the 6000 stars, which is visible to naked eye from the Earth.

The mass of Sun is 2 trillion trillion trillion tons.

The Sun's energy output is 386 billion billion megawatt.

The Earth receives 94 billion megawatts of energy from Sun. This is equivalent to 40,000 times the power requirement of United states.

The reaction taking place in Sun is nuclear fusion, same as a Hydrogen bomb.

Each second 700 million tons of Hydrogen are converted to 695 million tons of Helium and 5 million tons of energy in the form of gamma rays.

Each second the Sun loses 5 million tons of material.

The Sun's temperature at its core is 14 million Kelvin.

The pressure at the Sun's core is 340 billion times the pressure at the Earth's atmosphere.

The density of matter at the Sun's core is about 150 times the density of water in the Earth.

It takes up to 50 million years for the energy produced at the core of the Sun to reach its surface.

If the Sun were to stop producing energy today, it would take 50 million years for significant effects to be felt at Earth.

If a drop sized matter from the core of the Sun is placed on the surface of the Earth, no living organism will survive for a distance of 150 km from that drop.

The diameter of Sun is equivalent to the diameter of 109 earths.

The surface area of Sun is equivalent to that of 11990 earths.

The volume of Sun is equivalent to the volume of 1.3 million earths.

If the Sun were the size of a beach ball then Jupiter would be the size of a golf ball and the Earth would be as small as a pea.

The gravity at the surface of Sun is 28 times that of Earth.

A man weighing 60 kg in the Earth will weigh 1680 kg in the Sun.

The Sun makes up 99.86% of the mass of the solar system.

Unlike the Earth, the Sun is completely gaseous, there is no solid surface on the Sun.

By weight, Sun comprises of 73% hydrogen, 25% helium, 1.5% carbon, nitrogen, and oxygen, and 0.5% all other elements.

By volume, Sun comprises of 92.1% hydrogen, 7.8% helium and 0.1% all other elements.

The Sun is at a mean distance of 149.60 million km from Earth.

The light takes 8.3 minutes to travel from the Sun to Earth.

The Sun's gravitational pull is so strong that, even Pluto, a planet 5.9 billion kilometer away from Sun, is kept in it's orbit.

Escape velocity of any planet or star is the velocity required for any object to escape from the gravitational pull of that planet or star. The escape velocity of the Sun is 2.22 million km/hr.

The light takes 5.5 hours to travel from the Sun to Pluto, the outer most planet.

Proxima Centauri (Alpha Centauri C) is the star nearest to Sun. It is 4.3 light years away from Sun.

If our Sun were just an inch in diameter, the nearest star would be 445 miles away.

The Sun rotates about it's own axis once every 25.38 days.

The Sun exhibits differential rotation. The rotation period in the equator is about 25 days, whereas in the polar regions it is as high as 36 days.

The Sun orbits around the center of our Milky Way galaxy once every 240 million years.

The Sun is at a distance of 30,000 light years from the center of our Milky Way galaxy and lies on one of it's spiral arms.

The Sun along with the Solar family is orbits around our Milky Way galaxy at a velocity of 217 km/s.

The Sun has circled the Milky Way galaxy for about 20 times only since it's formation.

In addition to heat and light, the Sun also emits electrons and protons, known as the solar wind which travels at a speed of 450 km/sec.

Around a trillion neutrinos from the Sun will pass through your body while you read this sentence.

Solar flares are violent explosions taking place in the Sun's atmosphere occasionally. Solar flares can reach more than 100,000 miles away from the sun.

Sunspots appear as dark spots on the surface of the Sun. Sunspots are the intense magnetic regions of Sun with magnetic field strengths thousands of times stronger than the Earth's magnetic field.

Every eleven years, the magnetic poles of the Sun switch. This cycle is called "Solarmax".

The luminosity of the Sun is equivalent to the luminosity of 4 trillion trillion light bulbs of 100 watt.

All the coal, oil, gas, and wood on Earth would only keep the Sun burning for a few days.

An area of the Sun's surface the size of a postage stamp shines with the power of 1,500,000 candles.

The energy being emitted from 1 square centimeter of the Sun's surface is enough to burn 64 light bulbs of 100 watt.

The amount of the Sun's energy reaching the Earth's atmosphere (known as the Solar constant) is equivalent to 1.37 kw of electricity per square meter.

The amount of energy reaching the earth's surface from Sun is 6,000 times the amount of energy used by all human beings worldwide.

The total amount of fossil fuel used by humans since the first civilization is equivalent to less than 30 days of energy reaching the earth's surface from Sun.

If the sun stopped shining, all living organisms in the Earth would freeze to death, the tropics would be as cold as the poles, and the 7 seas would turn to solid ice.

In Spit Bergen, Norway at one time of the year the sun shines continuously for three and a half months.

At one time of the year, for 186 days you can not see the Sun in the North Pole of Earth.

Solar eclipses are visible in a narrow path, a maximum of 269 km wide.

No Total solar eclipse can last longer than 7 minutes and 40 seconds.

At any place on the Earth, a Total solar eclipse occur on an average of once every 360 years.

A maximum of 5 Solar eclipses only can occur in an year.

Among the Sun and the Moon, which one is larger, when viewed from our Earth ? Both are almost similar sized, when viewed from the Earth. Since the orbits of both Moon and Earth are elliptical, at certain times the Moon will be larger than the Sun and at certain other times the Sun will be larger than the Moon.

The age of Sun is 4.57 billion years.

The expected life time of Sun is another 5 billion years or so.

After 1.1 billion years from now, the Sun will be 10 % more brighter than today. The Earth's atmosphere will completely dry out as water vapour is lost to space.

After 3.5 billion years from now, the Sun will be 40 % more brighter than today. The oceans will evaporate into space and it means the end of all forms of terrestrial life.

After 5.4 billion years from now, the Sun's core will run out of Hydrogen.

After 7.7 billion years from now, the Sun will become a Red giant. It will expand by 200 times and it will engulf the planet Mercury.

After 7.9 billion years from now, the Sun will become a White dwarf. The orbital radius of other planets, including the Venus and the Earth will be almost double that of today.

The Sun will remain as a White dwarf indefinitely after 7.9 billion years.

How come we aren't dizzy then? Is it because we are so used to it? Is it because we're inside this movement? If the earth stopped spinning, would walking around be like moving in dry concrete?

Absolutely, it's because we are used to it. Used to the atmospheric pressure that bears down on us at all times. We like to think that we'd be an equally proficient species in space. But the truth is that our human bodies don't do worth a shit in space without the Earthly physics affecting our bodies at all times. It's an underrepresented fact of space travel. The human body just goes to shit outside of Earth's atmosphere.

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When the human body is suddenly exposed to the vacuum of space, a number of injuries begin to occur immediately. Though they are relatively minor at first, they accumulate rapidly into a life-threatening combination. The first effect is the expansion of gases within the lungs and digestive tract due to the reduction of external pressure. A victim of explosive decompression greatly increases their chances of survival simply by exhaling within the first few seconds, otherwise death is likely to occur once the lungs rupture and spill bubbles of air into the circulatory system. Such a life-saving exhalation might be due to a shout of surprise, though it would naturally go unheard where there is no air to carry it.

In the absence of atmospheric pressure water will spontaneously convert into vapor, which would cause the moisture in a victim’s mouth and eyes to quickly boil away. The same effect would cause water in the muscles and soft tissues of the body to evaporate, prompting some parts of the body to swell to twice their usual size after a few moments. This bloating may result in some superficial bruising due to broken capillaries, but it would not be sufficient to break the skin.

A NASA altitude chamber
Within seconds the reduced pressure would cause the nitrogen which is dissolved in the blood to form gaseous bubbles, a painful condition known to divers as “the bends.” Direct exposure to the sun’s ultraviolet radiation would also cause a severe sunburn to any unprotected skin. Heat does not transfer out of the body very rapidly in the absence of a medium such as air or water, so freezing to death is not an immediate risk in outer space despite the extreme cold.
For about ten full seconds– a long time to be loitering in space without protection– an average human would be rather uncomfortable, but they would still have their wits about them. Depending on the nature of the decompression, this may give a victim sufficient time to take measures to save their own life. But this period of “useful consciousness” would wane as the effects of brain asphyxiation begin to set in. In the absence of air pressure the gas exchange of the lungs works in reverse, dumping oxygen out of the blood and accelerating the oxygen-starved state known as hypoxia. After about ten seconds a victim will experience loss of vision and impaired judgement, and the cooling effect of evaporation will lower the temperature in the victim’s mouth and nose to near-freezing. Unconsciousness and convulsions would follow several seconds later, and a blue discoloration of the skin called cyanosis would become evident.

At this point the victim would be floating in a blue, bloated, unresponsive stupor, but their brain would remain undamaged and their heart would continue to beat. If pressurized oxygen is administered within about one and a half minutes, a person in such a state is likely make a complete recovery with only minor injuries, though the hypoxia-induced blindness may not pass for some time. Without intervention in those first ninety seconds, the blood pressure would fall sufficiently that the blood itself would begin to boil, and the heart would stop beating. There are no recorded instances of successful resuscitation beyond that threshold.

Though an unprotected human would not long survive in the clutches of outer space, it is remarkable that survival times can be measured in minutes rather than seconds, and that one could endure such an inhospitable environment for almost two minutes without suffering any irreversible damage. The human body is indeed a resilient machine.

Many people find that, at the beginning and end of the day, a small lump of fluff has appeared in the navel cavity. The reasons for this have been the subject of idle speculation for many years but in 2001, Dr. Karl Kruszelnicki of the University of Sydney, Australia undertook a systematic survey to determine the ins and outs of navel lint. His primary findings were as follows:

Contrary to expectations, navel lint appears to migrate upwards from underwear rather than downwards from shirts or tops. The migration process is the result of the frictional drag of body hair on underwear, which drags stray fibres up into the navel.

Women experience less navel lint because of their finer and shorter body hairs. Conversely, older men experience it more because of their coarser and more numerous hairs.

Navel lint's characteristic blue-gray tint is likely the averaging of the colors of fibres present in clothing; the same color as clothes dryer lint.

The existence of navel lint is entirely harmless, and requires no corrective action.